The present invention relates to a new and improved construction of apparatus for measuring or measuring-out -- hereinafter generally simply referred to as measuring -- a predetermined volume of a liquid flowing through a conduit or line and further pertains to a method of operating the aforesaid apparatus.
During physical, chemical or medical measurements it may be necessary to measure a predetermined volume of liquid or to turn-on measuring apparatuses only during the throughpassage of a predetermined volume of the liquid. An example of this environment of use is the automatic counting of blood cells or particles. It also can be necessary to detect the flow rate of the liquid, i.e. the volume which flows through per unit of time. This is useful for instance in the case of capillary viscometers.